Liquid-level gauge



March 23, 1954 H. J. JOHNSON 2,672,757

LIQUID -LEVEI.. GAUGE Filed June 26, 1951 IN V EN TOR. /%)'d6'6" Jms JJZWSO,

Patented Mar. 23,1954

UNITED G FFICE oomiggii p signor,=-byw;mesne assi gnments, to Buflalo E'lipse Corporatioma corporation of New York Application June 26, 1951,- swarm). 233. 577

(01. ia-asby 3-Glaims. 7.1

Thepresent invention relates to direct view liquid 4 level gauges and constitutes an" improvement'upon thewinvention disclosed in' theap' plication of Howard ni Yoderg serial No; 5,207, filed: October 18; .1 1948'. v

The Yoder patent application di'scloses unique means for obtaining and maintaining an" adequate seal betweenaa" transparent gauge glass and a gauge body,zin1a direct viewiiliquid level gauge designed to'withstand very highpressures (of' the order, for example; of 15,000 'poundsper square" inch). The Yoder: invention utilizes a trapped res'ilientclgasket formed of a composition which would another of sufficient mechanical strength to withstand the pressure, it installed in a conventional manner; tbut -wh'ich is confined in such manner that 1 iti is efi'ectiv'ely protected against mechanical destruction by such pressure, and is urged into sealing engagementWith the sealed parts at all 'times,'-with an engagement pressure which" is proportional to the pres sure in the gauge,xthe arrangement beingsuch that the resilient :gasket: can accommodate 0on5- siderable variation in the positioning an'd di mensions of the parts -wheth'er due to initial differences in manufacturing: orwassembly -of the parts, or due to expansion aiid contraction under temperature changes. In the operation 0f such gauges of the' YQd'er -type, the-l lii'e of the aforementioned resilient gasket material is un'-' der some conditionslimited "by: the eifect there upon of the liquid in the gauge-body: The pres: ent invention aims to provide" a construction adapted to incorporate all of -the advanta ges of the gauge disclosed in the aforementioned Yode'r application but wherein the iliquid in the gauge body is efiectively: prevented :from causing deterioration'ofthe gasketing or 'of the gauge glass, either by chemical or mechanical action; despite which the pressure within' the-gaugebody is effective to pressurize the gasketingi 'toachieve the i highly effective sealing action inherent j in the r Yoder' inventiom as--mentioned previr'msly;

The foregoing I and" otherfobjects which will become apparentupon-consideration '01 the "present disclosure in it's entirety a are achieved by the utilization I of a resilientgasket is trapped ina rabbet} formed in the gauge body and opening into the liquid chai'n'b'er"in'a position to lie opposite anew-ace orthe gauge glass, these parts being constructed and arranged in accordance with tl-ie teachin' "of th'e Yoder dis-- closure; butl the rabbet being somewhat larger in proportion -to the cross eaction of the gasket and a unique shield, which is formed of relatively inert; flexible; transparent plastic material, being interposed between the gasket and the liquid chamberiin=the=interior of the body, such" shield also extending between the gasket and one? face of the rabb'et; the gasket being surrounded and confined by ta rigid but floating framemember which prevents the gasket from being extruded through the'space between the gauge glass and the body under the internal gauge pressure; and the flexible shield being designed to transmit the internal gauge pressure to the gasket '50 that the mechanical operation of the "gasket occurs in all essential respects as if xthe shield were not present at all, while the liquid level visible by" looking directly through the 'shield.

Inthe drawingi Figure 1- is' a-perspe'ctive view of a liquid level gauget'constru'cte'd in accordance with the present invention;

Figure? is a 'horizontal cross-sectional view on a larger :scale and partially broken away, taken substantially on the lindZ-Z of Figure 1 and lookingd-in the direction" of vthe arrows; and

Figure 3 is a perspective view of the shield, partially brokeraway;

Referring now tothe drawings," reference character Illdesignatesgenerally a transparent liquid levelgauge the'major structural components of which are ofaitype' well kno'wnin the art and which will i require -no detailed discussion, insofares: he-generalarrangementor the front and rear frame ipbrtions l 2g -ll 'a'nd interposed body I 6 tightly' scured together by" bolts [5 is concerned. As also conimoin the body it has a vertical slot like'liquid chamber 19 which is open front andrear; ina1ignment with vertical slot-like window-openmgs as 18, in=theframe members. Suitable nipple connections as 20, 22 are provided at the top and bottomof the gauge body forf -connecting the liquid chamber] [9 therein tothe vesselmotshown) the liquid level wherein is to' be indicated. 7

It will beappreciatewthat this inventionis also applicableto gauges of the closed-back type, and that description'of'my invention as applied to a single window willsuflice; inany event, to enable those'skilled in" thet'artto incorporate the invention readilyin' gauges differing in the indicated particulars and 'inj other respects.

In 'accordancewitn'thejteaching of the above mentioned Yodenpaten'tapplication; a rabbet 24 is formed in theface of thebodyf 'l 6' surrounding the slot-like liquid*chaniber 19. The flat face 26 of the gauge window glass 25 is wider and longer than the rabbeted portion of the body It and the glass is held in position across, but somewhat spaced from, the rabbeted face 28 of the body, being held against outward movement by the frame I2. The frame 12 is suitably recessed as indicated at 30 to accommodate the gauge glass and a cushioning gasket 32 which is interposed between the opposite or outer face of the gauge glass and the frame. The cushioning gasket is appropriately slotted in registry with the window opening. The recess 30 is somewhat deeper than the combined depth of the gauge glass 25 and cushioning gasket 32. By virtue of the slight excess depth of the recess 30, a space 33 is left between the respective opposed faces 26, 28, of the gauge glass and body.

A deformable gasket 34 of synthetic rubber or the like is contained in the rabbet 24. Surrounding gasket 34 and accurately fitted in the rabbet 24 in such manner as to be slidable inwardly and outwardly of the rabbet, in a direction perpendicular to the gauge glass, is a floating frame 38 of right-angular cross-section, rigidly formed of metal and serving to confine the gasket 34 against unwanted expansion. On flange 35 of the floating frame 38 lies against the outer walls of the rabbet, and a second flange 36 extends inwardly between a portion of the gasketing material and the gauge glass, and lies flat against the inner face 26 of the gauge glass.

A transparent shield 40 is provided, the general shape of which is best indicated in Figure 3. Shield 40 isolates the chamber space it! from the gasket 34 and from gauge glass 25, and. is so contoured as to lie fiat against the inner surfaces of the gasket and gauge glass which would otherwise be exposed to the interior of the chamber space. The pressure within the chamber is accordingly transmitted to the gasket and gauge glass through the shield in compression. As shown in Figure 2, the shield is of double bent cross-section, having a flat peripheral flange portion 42 projecting into and lying in the flat bottom of the rabbet under the gasket 34. A vertically projecting flange portion 44 of the shield bounds the inner wall of the gasket 34 to define in effect a continuation of the wall of chamber [9. The vertical height of flange 44, in a direction perpendicular to the plane of the gauge glass, substantially corresponds to the normal or intended mean distanc between the bottom of the rabbet 24 and the opposing face 26 of the gauge glass. An integral transverse web portion 45 joins the vertical flange portions 44, to impart to the shielding member the contour of an elongated hat and complete the isolation of the material in the chamber. Such material can thus only contact the walls of chamber l9 and the shield, and is effectively prevented from contacting either the gasket or glass. The shield is preferably formed of a transparent material which is substantially inert with respect to and unaffected by the contents of the gauge chamber, and which is sufiiciently flexible so that pressure in the chamber is transmitted through the shield to the resilient gasket 34'. The resultant pressurizing of the gasket 34 causes the latter to tightly seal against the face 26 of the gauge glass and urges the flange 42 tightly against the bottom of the rabbet 24, effectively sealing these portions.

The confining floating frame 38 prevents any extrusion of the gasket 34 through the gap 33 and by its ability to move perpendicularly to the face 28, the floating frame compensates for differences in th space defined by the gap 33. Variances in the gap 33 may be due, for example, to temperature changes or to variances in dimensioning of the parts.

I have found that for most purposes, a plastic such as monochlortrifiuoroethylene is a suitable material for the shielding member 40, since such material is highly inert, transparent, flexible, and yet has great structural strength, so that it is neither chemically attacked nor easily eroded by most substances. Such material is sold by the M. W. Kellogg Company of Jersey City, New Jersey under the trade-name Kel-F, by the Bakelite Division of Union Carbide and Carbon Corporation under the trade-name CF-3, and by the Carbide and Carbon Chemical Division of Union Carbide and Carbon Corporation under the trade-name Fluorothene.

I have utilized gauges constructed in accordance with the present disclosure to indicate the liquid level in high-pressure vessels containing hydrocarbon materials which would rapidly deteriorate the synthetic rubber gasket 34, and have operated the same for extended periods at pressures of the order of 15,000 pounds per square inch with no deterioration of the seal, and no leakage or other difiiculty. The gauge retains both its transparency and its efliciency over substantial periods of time.

It will be appreciated that other materials might be employed for the shield, the primary consideration being the selection of a material which is not harmfully affected by the material in the gauge, yet is highly transparent, flexible and of sufficient mechanical strength to withstand the pressures encountered in service. It

will also be understood that the invention is susceptible of further variation, modification and change without departing from the spirit and scope of the subjoined claims.

I claim:

1. A direct view liquid level gauge including a body having an internal chamber and a window opening communicating with the chamber, a window element adapted to substantially cover the window opening and to extend in a position relatively close to but spaced from a portion of the body surrounding the window opening, means for holding said window element against movement away from the window opening, a resilient gasket interposed between the window element and said portion of the body surrounding the window opening, at least a portion of said gasket being in pressure-conductive communication with the chamber in the body and distortable by pressure in the chamber to react against the window and against said portions of the body surrounding the window opening when subjected to such pressure, a flexible transparent shield interposed between said gasket and the chamber in the body, an integral portion of said shield extending between said gasket and said portion of the body surrounding the window opening and another integral portion of the shield blocking communication between the chamber and the line of juncture of the gasket with the windows.

2. A direct view liquid level gauge including a. body having an internal chamber and a window opening communicating with the chamber, a window element adapted to substantially cover the window opening and to extend in a position relatively close to but spaced from a portion of the body surrounding the window opening, means for holding said window element against movement away from the window opening, a resilient gasket interposed between the window element and said portion of the 'body surrounding the window opening, at least a portion of said gasket being in pressure-conductive communication with the chamber in the body and distortable by pressure in the chamber to react against the window and against said portions of the body surrounding the window opening when subjected to such pressure, a flexible transparent shield interposed betwee said gasket and the chamber in the body, an integral portion of said shield extending between said gasket and said portion of the body surrounding the window opening and another integral portion of the shield interposed between the chamber and the window.

3. A direct view liquid level gauge including a body having an internal chamber and a window opening communicating with the chamber, a window element adapted to substantially cover the window opening and to extend in a position relatively close to but spaced from a portion of the body surrounding the window opening, means for holding said window element against movement away from the window opening, a resilient gasket interposed between the window element and said portion of the body surrounding the window opening, a resilient shield formed of flexible transparent material and of stepped cross section having a marginal flange portion adapted to project between the gasket and the body, an oifset central portion adapted to lie against the inner face of the window element, and a connecting portion integral with both said last two previously mentioned portions adapted to bear against the portion of the gasket which extends between the body and window element, whereby said shield isolates the chamber from both the window element and the gasket, and whereby pressure in the chamber may be transmitted through said flexible shield to the gasket.

HORACE JAMES JOHNSON.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,195,911 Comp Aug. 22, 1916 2,201,542 Kinderman May 21, 1940 2,579,719 Yoder Dec. 25, 1951 FOREIGN PATENTS Number Country Date 257,414 Germany Jan. 24, 1912 570,387 Great Britain July 4, 1945 

